November 15, 2007

Colossus Crack!

For the first time in more than 60 years a Colossus computer is cracking codes at Bletchley Park.

The machine is being put through its paces to mark the end of a project to rebuild the pioneering computer. It is being used to crack messages enciphered using the same system employed by the German high command during World War II.

The Colossus is pitted against modern PC technology which will also try to read the scrambled messages.

Colossus is widely recognised as being one of the first recognisably modern digital computers and was developed to read messages sent by the German commanders during the closing years of WWII. It was one of the first ever programmable computers and featured more than 2,000 valves and was the size of a small lorry.

The re-built Colossus will be put to work on intercepted radio messages transmitted by radio amateurs in Paderborn, Germany that have been scrambled using a Lorenz SZ42 machine - as used by the German high command in wartime. The German participants in the code-cracking challenge will transmit three enciphered messages - one hard, one very hard and one ultra hard.

Very cool. Crypto is my absolute favorite subject in information security, and I've always been particularly fascinated with its history during WWII. In fact, one of my heroes, Alan Turing, was an important part of the efforts at Bletchley:

The day after the war broke out Turing "joined up" full time at the Government Code and Cypher School, which had just moved to Bletchley Park. He was in the first handful of the stream of able mathematicians drafted into their code-breaking operations. In the next three years Turing was the key figure in the continual battle to decode messages encrypted by the increasingly complex Enigma machines, using the 'Bombe' machine. In particular he took charge of the most difficult code-breaking task, the breaking of the German naval codes. The Bombe was an electro-mechanical device, developed by Turing with help from another mathematician W. G. Welchman, inspired by the Polish 'Bomba'. The periods when the Naval code could be broken saw dramatic reductions in the shipping losses from the Atlantic convoys so essential to the conduct of the Allied war effort.

In November 1942 Turing went to the States for four months, to liaise at the highest level on the current U-boat crisis and on a proposed scrambling device they were building to maintain secrecy in conversations between Churchill and Roosevelt. At this time all other Enigma signals but the German Navy's were being routinely decoded, but the Navy had increased their complexity in February 1942, and the ability to decode their signals had then been lost and had not yet been restored. By the time Turing returned to the U.K., the ability to decode had been restored, under his deputy, and his deputy remained in charge. Turing moved on to a general consultancy role, and to work on a Speech Secrecy system. The American system comprised three roomfuls of equipment (one each for the White House, Pentagon and Whitehall), and Turing thought up a much smaller electro-mechanical device, about the size of a typewriter, which would obviously make the facility more widely available!

Turing was therefore not actively involved in the Colossus project (1943-45) directed by Max Newman, to decode the second generation of German coded communications, which were based on Lorenz machines. These used a completely different mechanism and methodology from the Enigma machines, and correspondingly their codes were broken using a completely different mechanism and methodology. Note however that the decoding procedures for both the Enigma and Lorenz involved imaginative, elaborate and sophisticated theories and processes, and the mechanical device used to provide the initial breakthrough for a new code (i.e. the Bombe and the Colossus respectively) was only one part of a complex operation. Turing made major theoretical contributions to the solution of both the Enigma and Lorenz codes; but whereas he made the key contribution to the design of the Bombe, which was a highly specific electro-mechanical device that bore little relation to a computer, ironically he was little involved in the design of Colossus, which was in effect a special purpose electronic digital computer.

None of the machines developed at that time were fully-fledged Turing machines, but he worked out a lot of the logical problems necessary to create even the single-purpose computers, let alone general purpose devices we use today.